Process of treating spinnerets



Patented Mar. 14, 1933 I ED STATES PATENT JEAN mmmrrn; or PEAGE DEnOUssILLoN, FRANCE, AssIGNoR To nuv ronr RAYON COMPANY, OF NEW YORK, n.Y., A CORPORATION, or DELA A 1 rnociiss or rnm'rmesrmimnnrs" No Drawing.

This invention relates to'the art of produc-- ing artificial thread bythe dry spinning process. More particularly, it relates to a method oftreating thespinnerets so that the spinning solution is such that thefilaments or thread may be conveniently'formed upon extrusion and duringarelati-vely short travel in an evaporative medium,'such as is presentin the spinning cell or otherdevice, whereby the volatile ingredientsarewholly or partly dissipated. v

The easy volatility of the liquid components of the spinning solutionis, however, a liability to the extent that the spinning solutionfrequently deposits the solute in the orifices of the spinnerets oron'the surfaces thereof. As a result, non-uniform thread, occasioned bythe interrupted and non-continuous production of filaments, is produced.For example, in starting a spinning position in operation, the spinningsolution issuing from the orifices of the spinneret, even though it beclean and clear, has a tendency to spread over the face of the spinningdie instead of issuing therefrom as a column 40f liquid or a partiallyformed thread or filament. Frequently, during operation of a spinningposition one or more of the orifices in the spinneret become wholly orpartly closed and the same phenomenon of the spinning solution crawlingalong the surface of the spinneret and/or building-up around theorifices occurs. Usually this phenomenon proceeds to a point where otherorifices of the same spinneret are involved. In any case, there resultsa situation which must be corrected in order to have successfulspinning.

Applicatiori filed March 19, 1931. Serial No. 523,937.

Prior to this invention, an 'atternptf'was-j made to overcome theabove-mentioned difficulty-by 'either' dipping the spinneret, and Iparticularly the face thereof, in a solvent for the materialconstituting the mass of thread or by wiping the face of the spinneretwith a cloth which'has beenwetted with th'e' SOIj vent. This practice isnot' very satisfactory','

Not only does it require ;considerable time and labor in'getting theposition into proper operation, but there results a large amount ofwaste in the-form of- -inferior-and unmarketable materials. i

The problem has been attempted to: be 7 solved by applying-a vacuum tothe spinneret until the orifices are clean and clear. In actualpractice, a-solvent was applied to the face of the spinneret prior toapplying the vacuum. This procedure requiredadditional paratus. A I:

I have found that by applying a ,nonsolvent ofthe solute of the solutionwhich constitutesthe mass of the thread, and either subsequentlyorsimultaneously wiping the face of the spinneret, Ican easily,'quicklyand effectively bring the spinneret in condi tion for proper andsuccessful spinning. l

It'is therefore an object of this invention to provide a simple method,without the use of any auxiliary expensive apparatus, of treatingspinnerets whereby they"may be. quickly" and efiectively brought intoproper condition for successful-spinning; f

'A specific object of thisinventioii is to provide a method of bringing"the s'pinneret into the;.necessary condition for successful i spinningwhich comprises applying a nonsolvent of the material constitutingthemass ofjthe thread and .either simultaneouslyor subsequently wiping theface of the spinneret.

Other objects will appear fromithe following description and appendedclaims.

As. is apparent: from the: foregoing ob;

comprises treating the spinneret, and .par-; ticularly the face thereof,preferably. while in spinning position'with a non-solvent for thematerial constituting the mass of the jects, the method constitutingthisinvention i thread and either simultaneously or subsequently wipingthe face of the spinneret.

Instead of diluting the spinning solution or re-dissolving a deposit ofthe solute to form a dilute solution which may again produce the badcondition, the non-solvent precipitates the solute in place and permitsthe precipitate to be subsequently removed.

In actual practice, for example, when a spinning position is begun inoperation, the

face of the spinneret or a portion thereof may be wiped one or moretimes with a cloth Wetted with a non-solvent for the materialconstituting the mass of the thread. The non-solvent precipitates thesolute and the mechanical action occasioned by wiping the cloth acrossthe face of the spinneretremoves the precipitated mass. 'As amodification of the aboveprocedure, the face of the spinneret may bedipped or immersed in a small receptacle containing a non-solventand'subsequently removing the precipitated mateas it issues from thespinneret.

rial from the spinneret in any suitable manner, such as by Wiping withacloth.

,I do not know the exact reason why the above-described proceduresproduce satisfac 'tory results.- It may be that in addition to removingthe precipitated materials the face of the spinneret is coated with athin film of the non-solvent which produces an interfacial tensionbetween the spinning solution and the so -coated spinneret that thespinning solution tends to remain in the form of a column of liquid orpartly formed thread .111 the production of artificial thread fromcellulose acetate by the dry spinning process, I find that I can quicklybring the spinnerets in proper spinning conditions by employing, asabove described, any one-of anumber the ethers, such as benzylcellulose, butyl,

cellulose and the like. When these cellulose derivatives are spun, it isonly necessary to select a material which is a non-solvent therefor asexplained hereinabove.

Since it is obvious that various changes may be made in the specificdetails abovedescribed without departing from the nature or spirit ofthe invention, the invention is not restricted thereto except as definedin the appended claims. v

I claim:

1. A method of bringing a spinnereteme ployed in the dry spinningprocess into prop= er spinning condition, either substantiallyimmediately prior to the beginning of spinning or at any necessary timeduring spinning, which comprises applying to the face of the spinneretin spinning position a nonsolvent for the solute in the. spinning solution and wiping the face of said spinneret.-

2. A method of bringing a spinneret emproper spinning condltion, eithersubstantially immediately prior to the beginning of spinning or at anynecessary time during spinning, which comprises simultaneously applyingto the face of the spinneret in spin ning position a non-solvent for thesolute in the spinning solution and wiping the face of, said spinneret.e 3. A method of bringing ployed in the dry spinning process into properspinning condition,;either substantial- -ployed in the dryspinningprocess into a spinneret em-l ly immediately. prior to the beginning ofsp nning or at any necessary time during spmnmg, which comprisesapplying to the face of the spinneret in splnnmg position a non-solventfor the solute in the spinning solution and then wiping the face of saidspinneret. v v I 4. A method'of bringing a spinneret employed in the dryspinning process into prop-v er spinning condition, either substantiallyimmediately prior to the beginning of spinning or, at any necessary timeduring spinning, which comprises wiping the face of the spinneret inspinning position with a cloth Wetted with a non sol-vent for the.solute'in the spinning solution.

In testimony whereof, I 'have aflixed my signature to thisspecification. V V 7 JEANLADRETTE.

